This invention is concerned with a chuck assembly for a drill box of a mine drill for releasably securing a mining tool of a type having a working end and a depending rod-like member. As used herein the term "mine drill" refers to a mining machine for rotatably powering the mining tool. Examples of well known mining tools commonly utilized in a mine drill include roof bolts and wrenches for roof bolting operations and drill bits for roof and face drilling operations and the like. The mining tool is operatively connected to the drill box of the mine drill through a male/female mechanical coupling, e.g., an end of the rod-like member includes a male fitting to engage a similarly configured female fitting associated with the drill box of the mine drill. In operation, rotary power is transferred to the mining tool through the mechanical coupling of the rod-like member of the mining tool to the drill box of the mine drill.
Heretofore known drill boxes of the mine drill require the coupling type mechanical connection as previously described to transfer rotary power to the mining tool. It will be appreciated that because the known mine drills require a coupling type mechanical connection, different mining tools having different size male fittings may not be used on the same mine drill without the use of an adaptive coupling to provide a proper fit and mechanical interlock. Accordingly, to provide a proper fit and mechanical interlock between a selected size female fitting of a drill box and a different size male fitting of a mining tool, the drill box of the mine drill may either be substituted with a different drill box having an appropriately sized female fitting or the female fitting of the drill box or the mine drill may be replaced with an appropriately sized fitting to accommodate the male fitting of the rod-like member. Substitution of the drill box of the mine drill or replacement of a female fitting of the drill box of the mine drill results in excessive down time in the drilling operation and contributes to inefficiency in the drilling of a work surface or installation of a mine roof bolt in the face of a mine.
In addition to the foregoing problems, in many instances, during the drilling operation or the installation of a mine roof bolt the rod-like member becomes disconnected from the drill box of the mine drill due to the rod-like member deflecting during the drilling operation because the axis of the hole formed by the drilling operation is not aligned with the central axis of the female fitting of the drill box of the mine drill. Once the rod-like member becomes disconnected from the drill box of the mine drill the rod-like member may become lodged within the drilled hole such that the only method of removing the rod-like member from the drilled hole is to reconnect the rod-like member to the drill box of the mine drill and reverse power the rod-like member from the drilled hole. Reattachment of the drill box of the mine drill to the rod-like member is a cumbersome and time consuming process that requires that the female fitting and the male fitting be manually axially aligned, often, in close quarters.
Each of the foregoing problems, along with numerous other problems inherent in the mechanical coupling arrangement of the prior mine drills and mining tools are known to adversely effect the speed and efficiency of operatively connecting a mining tool to the drill box of the mine drill thereby adversely effecting mining productivity.
The present invention, intended to address the problems of the prior art, includes a chuck assembly that may be used with a drill box of a mine drill such as a mine roof or rib bolting machine or a face drilling machine to directly grip the rod-like member of the mining tool instead of using a mechanical coupling arrangement. The chuck assembly in accordance with the present invention also allows the same drill box of a mine drill to utilize a variety of diametrical sizes and cross sectional configurations of rod-like members without need for the use of an adaptive coupling or for changing the male coupling of the rod-like member.
The chuck assembly in accordance with the present invention also mechanically aligns the rod-like member axis with respect to the axis of the drill box of the mine drill without requiring that the axes of the rod-like member and the drill box of the mine drill be manually aligned and that each male/female mechanical coupling be manually connected as previously performed. The chuck assembly allows for the rapid mechanical alignment of the drill box of the mine drill and the rod-like member by collapsing the chuck assembly uniformly around the rod-like member with sufficient force to grip the rod-like member evenly thereby automatically aligning the axes of the rod-like member and the drill box of the mine drill to enable the rod-like member to be rotated or removed from the drilled hole as desired.